Funding is requested for a Hewlett-Packard Model 5989A "MS Engine" mass spectrometer. This equipment will be the centerpiece of a Carcinogen Dosimetry Laboratory to be established at the American Health Foundation. The new laboratory will be dedicated to the quantitation of carcinogen- protein adducts and carcinogen-DNA adducts in humans. The major user group consists of seven scientists funded by NIH and carrying out projects concerned with carcinogen dosimetry. The present instrumentation, a Hewlett-Packard Model 5988A is used for many other projects at the Foundation and cannot possibly accommodate the tremendous volume of samples that will be generated in the ongoing and proposed dosimetry studies. In addition, the MS Engine is a state of the art instrument which has several performance features which are greatly superior to the 5988A. These include higher sensitivity, especially in the critical negative ion chemical ionization mode, an HPLC/MS interface not available on our current instrument, and improved automation and operational features which will greatly facilitate sample analysis. The new technology that will be developed with the MS Engine is expected to lead to major advances in our understanding of causes of human cancer.